Cleaning search info

I have used Brave web browser and DuckDuckGo for several years. I noticed today, while on a new web site that I went to that when I use their search engine and click in the search box my old search criteria for another site shows up. I haven’t found where to clear this in my brave browser. If I go to the new site using Chrome or my MS browser this does not happen.
To try resolving the problem I have deleted the browser from my computer and ensured the Brave file in the Program files were removed. Some of them were still there and I deleted them manually. I then downloaded a new copy of Brave and installed it. This did not solve the problem. Additionally, all of my bookmarks were in the fresh Brave Browser and, if this is truly a secure browser, I do not understand why the freshly downloaded browser had the old bookmarks. Can someone help.